Littelfuse 0452004.MRL Surface Mount Board Mount Fuse Equivalent & Substitute Parts

Part Overview

The Littelfuse 0452004.MRL is a 4 A, 125 V AC/DC surface mount board mount fuse in the NANO²® 452 series. This component is classified as Active and is supplied in Cut Tape (CT) & Digi-Reel® packaging. The fuse provides slow blow response characteristics with a 2-SMD, Square End Block package configuration suitable for PCB integration in low-voltage circuit protection applications.

Substitute parts become necessary when the primary part number reaches inventory constraints, when packaging format requirements differ between manufacturing stages, or when design revisions require alternative series within the same electrical specification envelope.

Substiute Parts

0452004.MRL

Littelfuse Inc.In Stock: 430300452004.MRL Datasheet

Current PartRFQ

0449004.MR

Littelfuse Inc.In Stock: 28000449004.MR Datasheet

Parametric EquivalentRFQ

0452004.NRL

Littelfuse Inc.In Stock: 307040452004.NRL Datasheet

Parametric EquivalentRFQ

0454004.MR

Littelfuse Inc.In Stock: 302880454004.MR Datasheet

Parametric EquivalentRFQ

TR1/6125TD4-R

Eaton - Electronics DivisionIn Stock: 4246TR1/6125TD4-R Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the 0452004.MRL is determined by the following critical parameters:

Primary Substitution Criteria:

• Current Rating: 4 A (exact match required)
• Voltage Rating AC: 125 V (exact match required)
• Voltage Rating DC: 125 V (exact match required for full compatibility)
• Response Time: Slow Blow (exact match required)
• Mounting Type: Surface Mount (exact match required)
• Package / Case: 2-SMD, Square End Block (exact match required)
• Breaking Capacity: 50 A (exact match required)

Secondary Considerations:

• Packaging format (Cut Tape vs. Tape & Reel) does not affect electrical compatibility
• Series designation (NANO²® 452, 449, 454) indicates manufacturing lineage but does not restrict substitution when electrical parameters align
• Melting I²t and DC Cold Resistance variations within the specified range are acceptable for equivalent operation

The substitute parts listed below meet all primary substitution criteria and are therefore electrically and mechanically interchangeable with the 0452004.MRL.

Parameter Comparison

Engineering Selection Recommendations

Littelfuse NANO²® Series (0449004.MR, 0452004.NRL, 0454004.MR):

These three parts are parametric equivalents to the 0452004.MRL with identical electrical specifications. All three maintain Active product status and carry CSA, PSE, and UL/UR certifications. Selection among these parts should be based on packaging requirements and inventory availability:

• 0452004.NRL is the direct equivalent in Tape & Reel format, maintaining the same NANO²® 452 series designation and identical DC Cold Resistance (0.0186 Ohms) and Melting I²t (34.4).
• 0454004.MR is available in Cut Tape format matching the original part's packaging, with identical electrical performance and certifications (CSA, PSE, UL).
• 0449004.MR is available in Tape & Reel format from the NANO²® 449 series. While electrically equivalent, it exhibits slightly higher DC Cold Resistance (0.0227 Ohms) and Melting I²t (40.8), remaining within acceptable operational parameters.

Eaton TR1/6125TD4-R:

This part carries Obsolete product status and features a reduced DC voltage rating of 60 V compared to the 125 V DC specification of the primary part. This part is suitable only for applications where DC voltage does not exceed 60 V. The part is no longer in active production and should be considered only when legacy system compatibility is required.

Frequently Asked Questions (FAQ)

Q: Can 0452004.NRL be used as a direct replacement for 0452004.MRL?

A: Yes. Both parts are from the NANO²® 452 series with identical electrical parameters: 4 A current rating, 125 V AC/DC voltage rating, slow blow response, and 2-SMD Square End Block package. The difference is packaging format: 0452004.NRL is supplied in Tape & Reel (TR) while 0452004.MRL is supplied in Cut Tape (CT) & Digi-Reel®. Electrical and mechanical compatibility is complete.

Q: What is the difference between the NANO²® 449, 452, and 454 series?

A: These designations indicate different manufacturing series within Littelfuse's product line. All three series share identical electrical specifications for the 4 A, 125 V AC/DC configuration. Series differences do not affect substitution eligibility when electrical parameters match. Differences in Melting I²t and DC Cold Resistance are minor and remain within acceptable operational ranges.

Q: Is the Eaton TR1/6125TD4-R suitable for all applications using the 0452004.MRL?

A: No. The Eaton part has a reduced DC voltage rating of 60 V compared to the 125 V DC rating of the Littelfuse part. Use the Eaton part only in applications where DC voltage does not exceed 60 V. The Eaton part is also Obsolete and should not be specified for new designs.

Q: Does packaging format affect electrical performance?

A: No. Cut Tape (CT) & Digi-Reel® and Tape & Reel (TR) packaging formats are logistics and handling variations only. Electrical and mechanical performance is identical. Selection should be based on manufacturing equipment compatibility and inventory requirements.

Q: What certifications apply to substitute parts?

A: Littelfuse NANO²® series parts (0449004.MR, 0452004.NRL, 0454004.MR) carry CSA, PSE, and UL/UR certifications. The Eaton TR1/6125TD4-R carries CSA and UL certifications. All parts are ROHS3 Compliant and REACH Unaffected. Verify certification requirements for your specific application before selection.

Q: Can I mix different series (449, 452, 454) in the same design?

A: Yes, provided all electrical parameters remain identical. However, for manufacturing consistency and traceability, it is preferable to standardize on a single part number within a design revision.